The primary issue regarding the plasma synthetic jet actuator(PSJA)is its performance attenuation at high frequencies.To solve this issue,a self-supplementing,dual-cavity,plasma synthetic jet actuator(SD-PSJA)is desig...The primary issue regarding the plasma synthetic jet actuator(PSJA)is its performance attenuation at high frequencies.To solve this issue,a self-supplementing,dual-cavity,plasma synthetic jet actuator(SD-PSJA)is designed,and the static properties of the SD-PSJA are investigated through experiments and numerical simulations.The pressure measurement shows that the SD-PSJA has two saturation frequencies(1200 Hz and 2100 Hz),and the experimental results show that both the saturation frequencies decrease as the volume of the bottom cavity of the SD-PSJA increases.As the size of the supplement hole increases,the first saturation frequency increases continuously,while the second saturation frequency shows a trend of first decreasing and then increasing.Numerical simulations show that the working process of the SD-PSJA is similar to that of the PSJA,but the volume of the cavity in the SD-PSJA is smaller than that of the PSJA;the SD-PSJA can supplement air to the top cavity through two holes,thus reducing the refresh time and effectively improving the jet intensity of the actuator at high frequencies.展开更多
A major issue of plasma synthetic jet actuator(PSJA)is the severe performance deterioration at high working frequency.In this study,experiments and numerical simulation are combined together to investigate the influen...A major issue of plasma synthetic jet actuator(PSJA)is the severe performance deterioration at high working frequency.In this study,experiments and numerical simulation are combined together to investigate the influence of thermal conductivity,throat length(Lth)and discharge duration(Td)on the high-frequency characteristics of PSJA.Results show that the variation of the actuator thermal conductivity and discharge duration will not alter the saturation frequency of the actuator,whereas decreasing the throat length results in an increase of the saturation frequency.For a short-duration capacitive discharge of 1.7μs,a clear shock wave is issued from the orifice,followed by a weak jet.As a comparison,when the discharge duration is increased up to 202.6μs,a strong jet column is formed and no obvious shock wave can be visualized.Based on numerical simulation results,it becomes clear that the long-duration pulse-DC discharge is able to heat the cavity gas to a much higher temperature(3141 K)than capacitive discharge,greatly improving the conversion efficiency of the arc discharge energy to the internal energy of the cavity gas.In addition,high-speed Schlieren imaging is deployed to study the performance degradation mechanism of PSJA at high working frequency.Monitor of the exit jet grayscale indicates that as long as the saturation frequency is exceeded,the actuator becomes unstable due to insufficient refresh time.The higher the discharge frequency,the more frequently the phenomenon of‘misfires’will occur,which explains well the decaying jet total pressure at above saturation frequency.展开更多
基金National Natural Science Foundation of China(No.61971345)the Foundation for Key Laboratories of National Defense Science and Technology of China(No.614220120030810).
文摘The primary issue regarding the plasma synthetic jet actuator(PSJA)is its performance attenuation at high frequencies.To solve this issue,a self-supplementing,dual-cavity,plasma synthetic jet actuator(SD-PSJA)is designed,and the static properties of the SD-PSJA are investigated through experiments and numerical simulations.The pressure measurement shows that the SD-PSJA has two saturation frequencies(1200 Hz and 2100 Hz),and the experimental results show that both the saturation frequencies decrease as the volume of the bottom cavity of the SD-PSJA increases.As the size of the supplement hole increases,the first saturation frequency increases continuously,while the second saturation frequency shows a trend of first decreasing and then increasing.Numerical simulations show that the working process of the SD-PSJA is similar to that of the PSJA,but the volume of the cavity in the SD-PSJA is smaller than that of the PSJA;the SD-PSJA can supplement air to the top cavity through two holes,thus reducing the refresh time and effectively improving the jet intensity of the actuator at high frequencies.
基金supported by National Natural Science Foundation of China(No.12002384)the National Key Laboratory Foundation of China(No.614220210200112)the Foundation Strengthening Project(No.2019-JCJQ-JJ-077)。
文摘A major issue of plasma synthetic jet actuator(PSJA)is the severe performance deterioration at high working frequency.In this study,experiments and numerical simulation are combined together to investigate the influence of thermal conductivity,throat length(Lth)and discharge duration(Td)on the high-frequency characteristics of PSJA.Results show that the variation of the actuator thermal conductivity and discharge duration will not alter the saturation frequency of the actuator,whereas decreasing the throat length results in an increase of the saturation frequency.For a short-duration capacitive discharge of 1.7μs,a clear shock wave is issued from the orifice,followed by a weak jet.As a comparison,when the discharge duration is increased up to 202.6μs,a strong jet column is formed and no obvious shock wave can be visualized.Based on numerical simulation results,it becomes clear that the long-duration pulse-DC discharge is able to heat the cavity gas to a much higher temperature(3141 K)than capacitive discharge,greatly improving the conversion efficiency of the arc discharge energy to the internal energy of the cavity gas.In addition,high-speed Schlieren imaging is deployed to study the performance degradation mechanism of PSJA at high working frequency.Monitor of the exit jet grayscale indicates that as long as the saturation frequency is exceeded,the actuator becomes unstable due to insufficient refresh time.The higher the discharge frequency,the more frequently the phenomenon of‘misfires’will occur,which explains well the decaying jet total pressure at above saturation frequency.
